vk/entry_points:: fix mingw build

MinGW does not play well either with weak symbols and crashes at runtime without a trace
fixes: 7e833713d8

Reviewed-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22474>

src/vulkan/util/vk_entrypoints_gen.py

@@ -50,7 +50,7 @@ extern "C" {
 % endif
 
 /* clang wants function declarations in the header to have weak attribute */
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
 #define ATTR_WEAK __attribute__ ((weak))
 #else
 #define ATTR_WEAK